How to use the pymemcache.exceptions.MemcacheUnknownError function in pymemcache

def test_get_unknown_error(self):
        client = self.make_client([b'foobarbaz\r\n'])

        def _get():
            client.get(b'key')

        pytest.raises(MemcacheUnknownError, _get)

        self.check_spans(1, ['get'], ['get key'])

if line == b'END' or line == b'OK':
                    return result
                elif line.startswith(b'VALUE'):
                    key, value, buf = self._extract_value(expect_cas, line, buf,
                                                          remapped_keys,
                                                          prefixed_keys)
                    result[key] = value
                elif name == b'stats' and line.startswith(b'STAT'):
                    key_value = line.split()
                    result[key_value[1]] = key_value[2]
                elif name == b'stats' and line.startswith(b'ITEM'):
                    # For 'stats cachedump' commands
                    key_value = line.split()
                    result[key_value[1]] = b' '.join(key_value[2:])
                else:
                    raise MemcacheUnknownError(line[:32])
        except Exception:
            self.close()
            if self.ignore_exc:
                return {}
            raise

buf = b''
            for key in keys:
                buf, line = _readline(self.sock, buf)
                self._raise_errors(line, name)

                if line in VALID_STORE_RESULTS[name]:
                    if line == b'STORED':
                        results[key] = True
                    if line == b'NOT_STORED':
                        results[key] = False
                    if line == b'NOT_FOUND':
                        results[key] = None
                    if line == b'EXISTS':
                        results[key] = False
                else:
                    raise MemcacheUnknownError(line[:32])
            return results
        except Exception:
            self.close()
            raise

def version(self):
        """
        The memcached "version" command.

        Returns:
            A string of the memcached version.
        """
        cmd = b"version\r\n"
        results = self._misc_cmd([cmd], b'version', False)
        before, _, after = results[0].partition(b' ')

        if before != b'VERSION':
            raise MemcacheUnknownError(
                "Received unexpected response: %s" % results[0])
        return after